8D report

What an 8D is

The eight disciplines (8D) is a team problem-solving method, first standardized in the automotive industry and now asked for by customers in many others. When a customer sends a complaint and asks for "an 8D", they expect this format: the disciplines in order, each with evidence, usually with deadlines for containment and for the root cause.

An 8D is heavier than a simple correction. Use it when the cause is unknown, when the problem has come back, or when the customer requires it. For a lighter internal record, the corrective and preventive action tool covers the same core steps in fewer fields.

The disciplines

• D0 Prepare: record the symptom and any emergency response, such as stopping shipment.
• D1 Team: a small cross-functional team with a champion who owns the resources and a leader who runs the work.
• D2 Describe: quantify the problem with 5W2H (what, why, where, when, who, how, how many) and an is / is not comparison. Describe the effect, not a guessed cause.
• D3 Contain: protect the customer now, everywhere suspect product can be, and verify the containment works.
• D4 Root cause: two verified causes: why it occurred, and why it escaped. The escape point is the first check in the process that should have caught it.
• D5 Choose and verify permanent corrective actions: prove, before full rollout, that each removes its cause without side effects.
• D6 Implement and validate: put them in and show in production that the problem is gone. Then remove the containment.
• D7 Prevent recurrence: fix the system that let it happen (FMEA, control plan, standards) and read the fix across to similar products and sites.
• D8 Recognize the team and close, with the champion's sign-off.

Verify and validate

The difference between D5 and D6 is the one most often blurred. Verification (D5) is evidence before implementation that the action works: a trial run, a test on returned parts. Validation (D6) is evidence after implementation, in normal production over enough time or volume, that the problem has not come back. An action that is implemented but never validated is a guess that has not been checked.

Three causes, not one

Most weak 8Ds stop at the occurrence cause. A complete one names three: why it happened, why the checks missed it, and why the system (the FMEA, the control plan, the design review) allowed both. The first two are fixed in D5 and D6; the third in D7.

Reading the status chart

Each discipline is shown as not started, in progress or complete, with the number of days from opening to completion. Red marks are the customer's due dates. The checks flag containment that was never verified, an escape point that is not named, actions implemented before they were verified, containment removed too early, and an 8D closed with disciplines still open.

On the exam

CSQP IV.C.2 names 8D among the methods for supplier corrective and preventive action, with updating the FMEA and control plan. CQPA V.A covers the corrective action process: identify, contain, find root causes, propose solutions, verify implementation and confirm effectiveness. CQE V.E covers problem identification, failure analysis, root cause analysis, recurrence control and verification of effectiveness, and CMDA III.D.9 covers CAPA under ISO 13485. Expect to put the disciplines in order, pick the step a given activity belongs to, and tell containment from corrective action.

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